The flotation principle as applied to the recovery of minerals or metals from ore has been known for the last century, an example of a known froth flotation apparatus being shown in Canadian Pat. No. 167,476 issued on Feb. 8th, 1916 to Minerals Separation American Syndicate (1913) Limited. This patent relates to the concentration of sulfide ores by froth flotation separation in which the ores are subjected to aeration in an aqueous separating medium in the presence of a frothing agent. The aeration is obtained by passing crushed ore, froth and water through a series of pipes between vertically spaced containers, each pipe having an intermediate open topped container so that air can be entrapped in the mixture by exposure at the open top of the container. The mixture with air therein then passes into the next container through a submerged outlet. This system does provide a certain amount of aeration to the mixture, however it has been determined since this patent that if more air can be entrapped in the mixture then more frothing will occur and a more efficient separation of the mixture will be possible.
Other methods of forming froth have been by aerating an ore mixture in an aqueous medium by vigorous agitation by means of stirrers, impellers, or beaters or by means of injection of compressed air generated by compressors and/or by means of utilizing high capacity centrifugal pumps. Such apparatus consume large amounts of power and are therefore expensive to operate.